Three new species of Hemicyclops, H. parilis, H. nasutus and H. membranatus are described from Korean coasts. Hemicyclops parilis n. sp. is closely similar to H. gomsoensis Ho and Kim, but distinguishable from the latter species by having the different shape of genital double somite and spermatophore. Hemicyclops nasutus n. sp. is distinguishable from congeners by having five setae on the first segment of antennule and the ratio 4.26 : 1 of the length to width of caudal ramus. Hemicyclops membranatus n. sp. is characterized by the possession of the membranous fringe along margins of cephalothorax and a claw on the third antennal segment.